Image forming apparatus, control method for image forming apparatus, and program configured to control power supply to components based on guaranteed time intervals

ABSTRACT

An image forming apparatus includes a first processing unit configured to execute a first type function, a second processing unit configured to execute a second type function different from the first type function, and a power supply unit configured to supply power to the first processing unit and the second processing unit, wherein a storage unit stores a first guaranteed time during which a power supply to the first processing unit is maintained and a second guaranteed time during which a power supply to the second processing unit is maintained, and a control unit configured to stop the power supply to the first processing unit when the stored first guaranteed time elapses and to stop the power supply to the second processing unit when the stored second guaranteed time elapses.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus, a controlmethod for the image forming apparatus, and a recording medium.

2. Description of the Related Art

A conventional image forming apparatus prioritizes user convenience andsimplification of a control operation. With such prioritization, theconventional image forming apparatus does not employ a configuration inwhich the start and stop of power supply are individually performed foreach component (e.g., a print apparatus and a scanner apparatus) of theimage forming apparatus.

In recent years, however, an image forming apparatus is expected toprovide a higher power-saving effect. Japanese Patent ApplicationLaid-Open No. 2001-201986 discusses an image forming apparatus in whicha power supply to each component is individually controlled by afunction operated inside the image forming apparatus. Such aconfiguration is expected to enable the image forming apparatus to havefurther power-saving effect.

The image forming apparatus includes consumable parts including anoperation part, such as a mechanical relay and a motor, and a part, forexample for a light source, which reaches a high temperature. Theconsumable part usually has an upper limit usage time of the number ofpower on and off operations with which the operation quality can beguaranteed.

However, the power supply may be controlled in the image formingapparatus having the configuration discussed in Japanese PatentApplication Laid-Open No. 2001-201986 such that the power supply isturned on and off repeatedly in a relatively short time. It is easy toimagine that such control causes the consumable part to exceed thenumber of endurance limit times thereof in a shorter time period than anestimated lifespan of the image forming apparatus.

In this case, the operation quality of the component of the imageforming apparatus cannot be guaranteed. As a result, a lifespan of theimage forming apparatus becomes shortened, causing technical difficultyin achieving both of further power-saving effect and prolonged lifespanof the image forming apparatus.

SUMMARY OF THE INVENTION

The present invention is directed to a configuration satisfying apower-saving requirement for an entire apparatus and achieving alifespan of each unit to be extended by controlling a power supply toeach unit according to a function selected by a user.

According to an aspect of the present invention, an image formingapparatus includes a first processing unit configured to execute a firsttype function, a second processing unit configured to execute a secondtype function different from the first type function, a power supplyunit configured to supply power to the first processing unit and thesecond processing unit, a storage unit configured to store a firstguaranteed time during which a power supply to the first processing unitis maintained and a second guaranteed time during which a power supplyto the second processing unit is maintained, and a control unitconfigured to stop the power supply to the first processing unit havingexecuted the first type function based on the first guaranteed timestored in the storage unit, and to stop the power supply to the secondprocessing unit having executed the second type function based on thesecond guaranteed time stored in the storage unit.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of an image formingapparatus.

FIG. 2 is a table illustrating a power-on state of each unit of theimage forming apparatus illustrated in FIG. 1.

FIG. 3 is a plane view illustrating a function selection screendisplayed on an operation unit of the image forming apparatusillustrated in FIG. 1.

FIG. 4 is a flowchart illustrating a control method for the imageforming apparatus.

FIG. 5 is a flowchart illustrating a control method for the imageforming apparatus.

FIG. 6 is a block diagram illustrating a power supply state of the imageforming apparatus.

FIG. 7 is a block diagram illustrating a power supply state of the imageforming apparatus.

FIG. 8 is a block diagram illustrating a power supply state of the imageforming apparatus.

FIG. 9 is a timing chart illustrating a power supply state of the imageforming apparatus illustrated in FIG. 1.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the inventionwill be described in detail below with reference to the drawings.

FIG. 1 is a block diagram illustrating an example of an image formingapparatus according to a present exemplary embodiment. In the presentexemplary embodiment, a multifunction peripheral (MFP) performingmultifunction image processing is described as an image formingapparatus 1.

In the present exemplary embodiment, the image forming apparatus 1includes a scanner apparatus 2, a printer apparatus 4, and an imageprocessing apparatus 5, as a plurality of processing units forperforming different types of functional processing. The multifunctionimage processing is performed by a combination of these processingunits. Moreover, the image forming apparatus of the present exemplaryembodiment includes a power supply device 6 for supplying power to eachof the processing units.

In the image forming apparatus 1 according to the present exemplaryembodiment, a user can select functional processing by using a userinterface (UI) screen displayed on an operation unit 8. The selectablefunctional processing includes copy function processing, facsimilefunction processing, transmission function processing, and box functionprocessing.

In FIG. 1, the scanner apparatus 2 optically reads an image from adocument, and converts the read image into a digital image. A controller3 executes a job on the image forming apparatus 1 by issuinginstructions to a facsimile (FAX) apparatus 7 and each module connectedto the controller 3. The facsimile apparatus 7 transmits a digital imageto a telephone line.

The printer apparatus 4 outputs a digital image to a paper medium. Theoperation unit 8 includes hard keys, a liquid crystal display (LCD) unitand the like to receive an operation instruction provided to the imageforming apparatus 1.

A hard disk device 14 stores digital images and control programs, forexample. The image forming apparatus 1 can input and output a digitalimage from and to a computer 10 via a local area network (LAN) 9.Moreover, the image forming apparatus 1 can issue a job and aninstruction for a device.

The scanner apparatus 2 includes a document feeding unit 11 whichautomatically and successively feeds a bundle of document sheets. Thescanner apparatus 2 also includes a scanner unit 12. The scanner unit 12optically scans an image on a document, converts the scanned image intoa digital image, and transmits the converted image data to thecontroller 3.

The printer apparatus 4 includes a feeding unit 18, a marking unit 16,and a sheet discharging unit 17. The feeding unit 18 can successivelyfeed sheets one by one from a sheet bundle, and the marking unit 16causes image data to be printed on the sheet fed from the feeding unit18. The sheet discharging unit 17 discharges the sheet on which theimage data is printed.

The controller 3 includes a central processing unit (CPU) 13. Thecontroller 3 transmits and receives image data to and from the scannerapparatus 2 and the printer apparatus 4, and stores the image data. Inthe controller 3, the image data received from the scanner apparatus 2is temporarily stored in a memory 15, and then stored in the hard diskdevice 14, thereby completing scanning and storing the image.

The controller 3 temporarily stores the image data in the memory 15 fromthe hard disk device 14, and transmits the image data from the memory 15to the printer apparatus 4. This enables the image forming apparatus 1to print out the image.

The image forming apparatus 1 includes the image processing apparatus 5including a general image processing unit 19. For example, the imageprocessing apparatus 5 can cause the general image processing unit 19 toreduce image data stored in the memory 15 and store the data again inthe memory 15. The general image processing unit 19 is used in varioussituations as necessary.

The image forming apparatus 1 includes the operation unit 8 controlledby the controller 3. The CPU 13 interprets an operator operation via theoperation unit 8 or an instruction from the LAN 9, so that the imageforming apparatus 1 can execute various jobs.

Examples of functional processing of the image forming apparatus 1 arehereinafter described. In the present exemplary embodiment, selectablefunctional processing includes copy function processing, facsimilefunction processing, transmission function processing, and box functionprocessing as described below. Each of the functional processing isexecutable in the image forming apparatus 1 according to the presentexemplary embodiment.

(Copy function)

The image forming apparatus 1 stores an image read from the scannerapparatus 2 in the hard disk device 14. Simultaneously, the imageforming apparatus 1 prints the image using the printer apparatus 4.

(Image Transmission Function)

The image forming apparatus 1 stores an image read from the scannerapparatus 2 in the hard disk device 14, and transmits the image to thecomputer 10 via the LAN 9.

(Image Storage Function)

The image forming apparatus 1 stores an image read from the scannerapparatus 2 in the hard disk device 14, and transmits or prints theimage as necessary.

(Image Printing Function)

The image forming apparatus 1 analyzes, for example, page descriptionlanguage data transmitted from the computer 10, and prints the analyzeddata using the printer apparatus 4.

(FAX Reception Print)

The image forming apparatus 1 stores a FAX image received from the FAXapparatus 7 in the hard disk device 14. Simultaneously, the imageforming apparatus 1 prints the FAX image using the printer apparatus 4.

(FAX Transfer Processing)

The image forming apparatus 1 stores a FAX image received from the FAXapparatus 7 in the hard disk device 14. Simultaneously, the imageforming apparatus 1 transfers the FAX image to the computer 10 via theLAN 9.

(FAX Memory Reception Processing)

The image forming apparatus 1 stores a FAX image received from the FAXapparatus 7 in the hard disk device 14, and waits for an operator toview the FAX image.

(FAX Transmission Processing)

The image forming apparatus 1 stores an image read from the scannerapparatus 2 in the hard disk device 14. Simultaneously, the imageforming apparatus 1 transmits the image to a public line from thefacsimile apparatus 7.

The hard disk device 14 is interposed in most of above-described cases.In this way, the image forming apparatus 1 can recover from a jobfailure and an abnormal situation such as power interruption.

The power supply device 6 supplies power to each unit in the imageforming apparatus 1.

When the image forming apparatus 1 is being powered off, an alternatingcurrent (AC) power supply 29 is insulated by a switch 30.

When the switch 30 is turned on, an AC power is supplied to analternating current direct current (AC-DC) converter 20, and a DC poweris generated. The image forming apparatus 1 can control the entireapparatus thereof with four independent power supplies according toinstructions of the CPU 13. More specifically, the CPU 13 can controlON/OFF of a power supply of a controller unit power 25 by a switch 21.

Similarly, a switch 22, a switch 23, and a switch 24 are used forcontrolling ON/OFF of power supplies for a printer unit power 28, ascanner unit power 26, and a general image processing unit power 27,respectively.

The CPU 13 uses these switches 21 through 24 for properly supplying thepower to a necessary unit in the image forming apparatus 1. In thepresent exemplary embodiment, each of the processing units serving as afirst processing unit and a second processing unit includes a switch forconnecting and disconnecting a power supply. When the copy function isselected, the CPU 13 controls the switches such that the power issupplied to each of the scanner apparatus 2, the printer apparatus 4,and the image processing apparatus 5.

Each power state is described below.

(Sleep State)

A sleep state is a power state in which power consumption of the imageforming apparatus 1 is reduced as low as possible.

A peripheral device of the CPU 13 is in a general suspend state (e.g.,an advanced configuration and power interface (ACPI)-S3), whereas only ajob detectable portion (a sleep time power 31) is in an energized state.Accordingly, the power consumption of the entire image forming apparatus1 can be very low.

Specifically, the CPU 13 stores a state of the image forming apparatus 1in the memory 15, and turns off the power of the controller unit power25 including the power thereof by using the switch 21.

In such a state, the CPU 13 stops the operation thereof, whereas a powersupply of the sleep time power 31 is turned on as hardware, so that theCPU 13 recognizes only job reception.

For example, when a job is received via the LAN 9, when the FAXapparatus 7 receives an incoming call, and when the operation unit 8 isoperated, the controller unit power 25 is turned on as hardware.

The CPU 13 reads out the state of the image forming apparatus 1 storedin the memory 15. Then, the CPU 13 performs resetting to cause the imageforming apparatus 1 to return to the state immediately before the powersupply of the controller unit power 25 is turned off, and the imageforming apparatus 1 shifts to a standby state.

Since most of the hardware cannot operate in the sleep state, onlyshifting to the standby state is performed. After being shifted to thestandby state, the image forming apparatus 1 receives a job.

(Standby State)

A standby state is a power state in which the controller unit power 25is being in an energized state.

The image forming apparatus 1 receives an operator's operation throughthe operation unit 8, and a job via the LAN 9.

Since the printer unit power 28, the scanner unit power 26, and thegeneral image processing unit power 27 are being turned off, the CPU 13turns on a power supply for each of the devices to be used by using theswitches 22 through 24 before executing a prescribed job. For example,the CPU 13 turns on a power supply for each of the devices according toa job type as described below.

(Copy Function)

The CPU 13 turns on the scanner unit power 26, the general imageprocessing unit power 27, and the printer unit power 28, so that theabove-described copy function is performed.

(Image Transmission Function)

The CPU 13 turns on the scanner unit power 26 and the general imageprocessing unit power 27, and read image data is transmitted.

(Image Storage Function)

The CPU 13 turns on the scanner unit power 26 and the general imageprocessing unit power 27, and read image data is stored.

(Box Printing Function)

The CPU 13 turns on the printer unit power 28 and the general imageprocessing unit power 27, and various image data pieces are printed.

(FAX Reception Print)

The CPU 13 turns on the printer unit power 28 and the general imageprocessing unit power 27. After general image processing is executed ona FAX image received by the FAX apparatus 7, the processed FAX image isprinted.

(FAX Transfer Processing)

The CPU 13 turns on only the general image processing unit power 27.After general image processing is executed on data received by the FAXapparatus 7, the processed FAX data is transferred.

(FAX Memory Reception Processing)

The CPU 13 turns on only the general image processing unit power 27.After general image processing is executed on data received by the FAXapparatus 7, the processed data is stored in the hard disk device 14.

(FAX Transmission Processing)

The CPU 13 turns on the scanner unit power 26 and the general imageprocessing unit power 27, so that FAX image data read by the scannerapparatus 2 is transmitted to a public line.

When the job is completed, the power supply to the device is turned off.This enables only the devices needed for the job to be in an energizedstate only when the device is used, thereby reducing the power consumedduring the standby state.

FIG. 2 is a table illustrating a power-on state of each unit of theimage forming apparatus 1 illustrated in FIG. 1. This diagramillustrates an example in which a state of a power supply system of eachcomponent in the image forming apparatus 1 is associated with a minimumguaranteed time according to a function selected via the operation unit8. The minimum guaranteed time is a power-on state time period to bemaintained for each component. Specifically, a guaranteed time and apower shift state are stored in a state storage unit, which will bedescribed below. The guaranteed time is a time period for which a powersupply for each processing unit is continuously performed. The powershift state indicates a state in which a power supply to each processingunit is shifted to ON or OFF according to a selected function. A powersupply state of each unit is described below. The minimum guaranteedtime and the power shift state illustrated in FIG. 2 are stored as atable in the hard disk device 14. However, the minimum guaranteed timeand the power shift state may be stored in another storage medium, forexample, a flash read only memory (ROM) or an electrically erasableprogrammable read only memory (EEPROM).

Moreover, after power is supplied to the image forming apparatus 1, thetable is read out from the hard disk device 14 to the memory 15 so thatthe table is managed to be available for the CPU 13.

A copy function selected state 204 in FIG. 2 corresponds to a case wherea user has selected a copy function. In the copy function selected state204, FIG. 2 illustrates that all of the components (i.e., the scannerapparatus 2, the printer apparatus 4, and the image processing apparatus5) are in a powered-on state.

Similarly, a FAX function selected state 206 corresponds to a case wherethe user has selected a FAX function. In the FAX function selected state206, FIG. 2 illustrates that the scanner apparatus 2 and the imageprocessing apparatus 5 are in a power-on state, while the printerapparatus 4 is in a power-off state (FIG. 8). In addition to thesestates, FIG. 2 illustrates a user authentication wait state, which is awaiting period for a function to be selected by a user, a transmissionfunction selected state, and a box function selected state 205.

Next, the minimum guaranteed time is described.

A guaranteed time represents a minimum time period for which a power-onstate is maintained when a power-off state is shifted to the power-onstate.

In FIG. 1, the scanner apparatus 2 includes a switch 32, and the printerapparatus 4 includes a switch 33. Each of these switches 32 and 33includes a mechanical relay. Since such a mechanical relay is aconsumable part, there is the number of endurance limit times, whichguarantees operation quality of the relay. The relay generally has thenumber of endurance limit times of approximately 200,000 times, althoughthe number of endurance limit times may be affected by an operationvoltage, an electric current, and an ambient temperature.

When it is presumed that a power supply is turned on and off 10 timesper hour while the image forming apparatus 1 operates eight hours perday. In this case, the relay performs ON/OFF operations for 29,200 timesper year, and thus reaches the number of endurance limit times in lessthan seven years.

When it is presumed that the image forming apparatus 1 has a lifespan ofsuch a length, the image forming apparatus 1 needs to maintain apower-on state for six minutes. Thus, a guaranteed time period of theprinter apparatus 4 becomes 360 seconds.

However, in a case where the guaranteed time is longer, a time periodbefore the image forming apparatus 1 shifts to a power-saving statebecomes longer. Since the longer guaranteed time causes an increase inpower consumption of the image forming apparatus 1, it is desired thatthe guaranteed time be as short as possible. A semiconductor relay maybe used instead of the mechanical relay to deal with such a situation.Since the semiconductor relay does not include a mechanically movablemember, the semiconductor relay is known to have the greater number ofendurance limit times as almost unlimited.

In the present exemplary embodiment, the image processing apparatus 5includes a switch 34 which includes a semiconductor relay. Thus, theimage processing apparatus 5 is set to have a minimum guaranteed time207 of five seconds as illustrated in FIG. 2. The guaranteed time 207illustrated in FIG. 2 for each of the first and the second typefunctions is an example. The guaranteed time 207 may be set according tospecifications of those members in the image forming apparatus 1.

FIG. 3 is a plane view illustrating a function selection screendisplayed on the operation unit 8 illustrated in FIG. 1.

The operation unit 8 of the present exemplary embodiment includesfunction selection buttons 2000, a numeric keypad 2020, a copy startbutton 2030, an operation stop button 2031, and a mode change button2040. Moreover, the operation unit 8 includes data input keys 2051 and2052, and one-touch dial buttons 2060. The operation unit 8 alsoincludes an LCD display unit 2010 capable of displaying various userinterfaces. A user uses the function selection button 2000 of theoperation unit 8 to select a function to be executed.

In FIG. 3, the function selection buttons 2000 are used when the userselects various functions, which are settable in the image formingapparatus 1. The LCD display unit 2010 displays a device state and adata input state. The LCD display unit 2010 of the present exemplaryembodiment can display a character string in two lines. The user usesthe numeric keypad 2020 to input numeric data and a FAX destinationnumber.

The user selects the copy start button 2030 and the operation stopbutton 2031 to activate and stop a device function. The user uses themode change button 2040 to change a device operation mode. Specifically,the mode change button 2040 is used when an operation mode, such asregistration setting mode and a normal operation mode, needs to bechanged.

In the registration setting mode, the user uses the data input keys 2051and 2052 to input characters. The user selects a character displayed onthe LCD display unit 2010 by using the data input keys 2051 and 2052.The user selects an OK button 2050 to confirm a displayed content.

The one-touch dial button 2060 is used when the user registers a FAXdestination. In FIG. 3, for example, a user can register up to three FAXdestinations. The user registers a telephone number of a frequently useddestination in each button. Such registration enables the user to omitan input of the telephone number of the frequently used destination,thereby simplifying an operation.

FIG. 4 is a flowchart illustrating a control method for the imageforming apparatus 1 according to the present exemplary embodiment. Theprocessing in this flowchart is not executed if the image formingapparatus 1 is executing print processing, or a user has just finishedoperating a user interface unit. The processing is periodically executedat intervals of unused states, for example, every five seconds. In acase where the user performs an operation, or a job is remotely executedin the course of the processing, the processing is ended byinterruption. The CPU 13 performs each processing in the flowchart byexecuting the control program stored in the hard disk device 14. In theflowchart, the CPU 13 repeatedly executes step S301 through step S307unless the processing is ended by interruption. Hereinafter, controlprocessing for preventing deterioration in operation quality of aconsumable part of the image forming apparatus 1 is described in detail.This control processing suppresses a case where a power supply isrepeatedly turned on and off in a relatively short time for eachcomponent of the image forming apparatus 1. Moreover, the CPU 13 refersto each of stored guaranteed times for the corresponding processingunits, and controls the power supply such that the power supply for eachprocessing unit is maintained. Such control processing is alsodescribed. In the present exemplary embodiment, each processing unit hasa corresponding function. The scanner apparatus 2 has a scannerfunction, the printer apparatus 4 has a print function, and the imageprocessing apparatus 5 has an image processing function. The user canset beforehand which component of the image forming apparatus 1 servesas a first processing unit or a second processing unit. Alternatively,the user can set that the first processing unit and the secondprocessing unit are changeable. Such settings can be made optionally.Moreover, guaranteed times for the respective first and secondprocessing units are called a first guaranteed time and a secondguaranteed time for the sake of simplicity.

In step S302, the CPU 13 acquires a time elapsed from the beginning ofthe processing. Since the elapsed time is not necessarily be an absolutetime, an internal counter register (not illustrated) inside the CPU 13is used in the present exemplary embodiment. Even if the absolute timeis applied, similar processing can be executed.

In step S303, the CPU 13 compares the acquired elapsed time with aguaranteed time of each component of the image forming apparatus 1. Theelapsed time represents a time elapsed from a state in which there isnot an operation request. The guaranteed time of each component isstored in the memory 15 as minimum guaranteed times 203 illustrated inFIG. 2. The scanner apparatus 2, the printer apparatus 4, and the imageprocessing apparatus 5 have the minimum guaranteed times of 300 seconds,360 seconds, and 5 seconds, respectively.

If the CPU 13 determines that the elapsed time acquired in step S302exceeds the guaranteed time of the scanner apparatus 2 (YES FOR SCANNERAPPARATUS in step S303), the operation proceeds to step S304. In stepS304, the CPU 13 executes power disconnection determination processingfor the scanner apparatus 2. The power disconnection determinationprocessing will be described in detail below.

Similarly, if the CPU 13 determines that the acquired elapsed timeexceeds the guaranteed time of the printer apparatus 4 (YES FOR PRINTERAPPARATUS in step S303), the operation proceeds to step S305. If the CPU13 determines that the acquired elapsed time exceeds the guaranteed timeof the image processing apparatus 5 (YES FOR IMAGE PROCESSING APPARATUSin step S303), the operation proceeds to step S306.

On the other hand, if the CPU 13 determines that the acquired elapsedtime does not exceed any of the guaranteed times (NO in step S303), theoperation proceeds to step S307. Subsequently, the CPU 13 repeatedlyexecutes the processing from step S301 to step S307.

FIG. 5 is a flowchart illustrating a control method for the imageforming apparatus 1 according to the present exemplary embodiment. Theflowchart describes in detail the power disconnection determinationprocessing executed by the CPU 13 in steps S304, S305, and S306illustrated in FIG. 4.

The processing illustrated in FIG. 5 is executed in a case where theguaranteed time has elapsed while there is no user operation or no jobexecution in step S303 of the flowchart illustrated in FIG. 4.

Processing operations in steps S304, S305, and S306 are similar to oneanother except for a referring item in the table during the processing,and a switch to be used when power supply control is actually performed.

The flowchart illustrated in FIG. 5 is described by using the powerdisconnection determination processing (step S304 in FIG. 4) of thescanner apparatus 2 as an example.

In step S401, the CPU 13 acquires a type of a function, which iscurrently selected by a user, of the image forming apparatus 1. Theselected function is, for example, a copy function and a FAX function.It is presumed that the copy function is selected in the descriptionbelow.

In step S402, the CPU 13 determines how to change a power supply stateof the scanner apparatus 2 corresponding to the selected function. TheCPU 13 performs such determination by referring to the table illustratedin FIG. 2.

In the copy function selected state 204, a power supply state 202 foreach function of the scanner apparatus 2 is internally managed as “ON”.Consequently, the CPU 13 determines that the power supply state remainsON (ON in step S402), and then the power disconnection determinationprocessing ends. A power state of the entire image forming apparatus 1at this time is illustrated in FIG. 6.

Next, the power disconnection determination processing performed when afunction selected in step S401 is in the box function selected state 205is described.

In step S402, the CPU 13 refers to the table illustrated in FIG. 2.Since the power supply state 202 for each function of the scannerapparatus 2 in the box function selected state 205 is internally managedas “OFF” (OFF in step S402), the CPU 13 determines that the powerdisconnection determination processing proceeds to step S403. In stepS403, the CPU 13 executes power disconnection processing. The switch 32inside the scanner apparatus 2 illustrated in FIG. 1 is turned “OFF”,and thus a power supply to the scanner apparatus 2 is disconnected. Apower state of the entire image forming apparatus 1 at this time isillustrated in FIG. 7. Moreover, in the FAX function selected state andthe transmission function selected state, if the CPU 13 determines thata power supply state is “OFF” in step S402 illustrated in FIG. 5, apower supply to the printer apparatus 4 is disconnected as illustratedin FIG. 8.

Therefore, the CPU 13 executes the control processing as illustrated inthe flowcharts in FIGS. 4 and 5 to individually disconnect a powersupply to each component of the image forming apparatus 1 only if aguaranteed time of each component has elapsed while the image formingapparatus 1 is not used for a certain time period.

FIG. 9 is a timing chart illustrating a power supply state of the imageforming apparatus illustrated in FIG. 1. This example chart illustratesa change in a power supply state of each component of the image formingapparatus 1 according to the control described with reference to FIGS. 4and 5.

In FIG. 9, a horizontal axis indicates a lapse of time, and timings (1)through (6) indicate operation timings of a user. In a case where theuser operates the operation unit 8 to select a FAX function at thetimings (1), (2), (4), and (6) and a copy function at the timings (3)and (5), power supply states change as illustrated in FIG. 9.

With using the copy function and the FAX function, a power supply stateof the scanner apparatus 2 remains the same, whereas a power supplystate of each of the printer apparatus 4 and the image processingapparatus 5 changes as illustrated in FIG. 2. Moreover, since the imageprocessing apparatus 5 has a shorter guaranteed time than the printerapparatus 4, the CPU 13 controls a timing such that the power supply tothe image processing apparatus 5 is disconnected earlier than that tothe printer apparatus 4. Moreover, as illustrated in FIG. 9, the usercan repeatedly select functions in a short time from the timings (2)through (6). Even in such a case, the CPU 13 compares an elapsed timewith the guaranteed time in step S303, and if the elapsed time is withinthe guaranteed time, the power disconnection processing is notperformed, so that a power supply state is maintained. Such processingprevents a decrease in durability of the consumable part.

According to the above-described processing, therefore, when a userselects a function to be executed, power supply control is executedaccording to the present exemplary embodiment. Such control suppresses acase where a power supply is repeatedly turned on and off in arelatively short time with respect to each component of the imageforming apparatus 1, thereby preventing a deterioration in operationquality of the consumable part.

Therefore, the power saving of the image forming apparatus 1 isachieved, and at the same time, lifespan of the image forming apparatus1 is prolonged in a well-balanced manner. Thus, user convenience ismarkedly improved.

The exemplary embodiments of the present invention can be performed by aprocessing apparatus (a CPU, a processor), such as a personal computer.In such a case, the processing apparatus executes software (a program)acquired through a network or various storage media.

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions recorded on a storage medium (e.g., non-transitorycomputer-readable storage medium) to perform the functions of one ormore of the above-described embodiment(s) of the present invention, andby a method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiment(s). The computer may comprise one or more ofa central processing unit (CPU), micro processing unit (MPU), or othercircuitry, and may include a network of separate computers or separatecomputer processors. The computer executable instructions may beprovided to the computer, for example, from a network or the storagemedium. The storage medium may include, for example, one or more of ahard disk, a random-access memory (RAM), a read only memory (ROM), astorage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2013-044574 filed Mar. 6, 2013, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image forming apparatus comprising: a firstprocessing unit configured to execute a first type function; a secondprocessing unit configured to execute a second type function differentfrom the first type function; a power supply unit configured to supplypower to the first processing unit and the second processing unit; astorage unit configured to store a first guaranteed time during which apower supply to the first processing unit is maintained, and a secondguaranteed time during which a power supply to the second processingunit is maintained; and a control unit configured to compare both thefirst guaranteed time to a first elapsed time from a state wherein thereis not an operation request of processing of the first type function,and the second guaranteed time to a second elapsed time from a statewherein there is not an operation request of processing of the secondtype function, to maintain the power supply to the first processing unitbefore the first guaranteed time stored in the storage unit elapsesafter the first processing unit executes the first type function and tomaintain the power supply to the second processing unit before thesecond guaranteed time stored in the storage unit elapses after thesecond processing unit executes the second type function, and to stopthe power supply to the first processing unit when the first guaranteedtime stored in the storage unit elapses after the first processing unitexecutes the first type function, and to stop the power supply to thesecond processing unit when the second guaranteed time stored in thestorage unit elapses after the second processing unit executes thesecond type function.
 2. The image forming apparatus according to claim1, wherein the first type function executed by the first processing unitis a print function.
 3. The image forming apparatus according to claim1, wherein the first processing unit is a printer.
 4. The image formingapparatus according to claim 1, wherein the second type functionexecuted by the second processing unit is a scanner function or an imageprocessing function.
 5. The image forming apparatus according to claim1, wherein the second processing unit is a scanner or an imageprocessing apparatus.
 6. The image forming apparatus according to claim1, further comprising: a selection unit configured to select the firsttype function or the second type function; and a state storage unitconfigured to store a power shift state providing an ON state or an OFFstate to which a state of the power supply to each of the first andsecond processing units is shifted according to the function selected,wherein, when a time during which an operation request is absent exceedsthe first and second guaranteed times of the first and second processingunits, the control unit controls the power supplied from the powersupply unit to the first and second processing units based on the powershift state corresponding to the selected function.
 7. A method forcontrolling an image forming apparatus including a first processing unitconfigured to execute a first type function, a second processing unitconfigured to execute a second type function different from the firsttype function, a power supply unit configured to supply power to thefirst processing unit and the second processing unit, and a storage unitconfigured to store a first guaranteed time during which the powersupply to the first processing unit is maintained, and a secondguaranteed time during which the power supply to the second processingunit is maintained, the method comprising: comparing both the firstguaranteed time to a first elapsed time from a state wherein there isnot an operation request of processing of the first type function, andthe second guaranteed time to a second elapsed time from a state whereinthere is not an operation request of processing of the second typefunction, controlling power supply such that the power supply to thefirst processing unit is maintained before the first guaranteed timestored in the storage unit elapses after the first processing unitexecutes the first type function, and controlling power supply such thatthe power supply to the second processing unit is maintained before thesecond guaranteed time stored in the storage unit elapses after thesecond processing unit executes the second type function, andcontrolling power supply such that the power supply to the firstprocessing unit is stopped when the first guaranteed time stored in thestorage unit elapses after the first processing unit executes the firsttype function, and controlling power supply such that the power supplyto the second processing unit is stopped when the second guaranteed timestored in the storage unit elapses after the second processing unitexecutes the second type function.
 8. A computer-readable non-transitorystorage medium storing a program that causes a computer to execute thecontrol method for the image forming apparatus according to claim 7.